package com.example.demo01;
import java.util.Map;
import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends ActionBarActivity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main1111);
}
class MyHelper extends SQLiteOpenHelper{
public MyHelper(Context context) {
super(context, "itcast.db", null, 1);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE information(_id INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(20),phone VARCHAR(20))");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
public void Click(View v) {
String name, phone;
MyHelper myhelper=new MyHelper(this);
EditText mEtName=(EditText)findViewById(R.id.editText2);
EditText mEtPhone=(EditText)findViewById(R.id.editText1);
TextView mTvShow=(TextView)findViewById(R.id.tv1);
Button mBtnAdd=(Button)findViewById(R.id.button1);
Button mBtnQuery=(Button)findViewById(R.id.button2);
Button mBtnUpdate=(Button)findViewById(R.id.button3);
Button mBtnDelete=(Button)findViewById(R.id.button4);
switch(v.getId()) {
case R.id.button1:
name = mEtName.getText().toString();
phone = mEtPhone.getText().toString();
SQLiteDatabase db = myhelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("name", name);
values.put("phone", phone);
db.insert("information", null, values);
Toast.makeText(this, "信息已添加", Toast.LENGTH_SHORT).show();
db.close();
break;
case R.id.button3:
db = myhelper.getReadableDatabase();
Cursor cursor = db.query("information", null, null, null, null, null, null);
if(cursor.getCount() == 0) {
mTvShow.setText("");
Toast.makeText(this, "没有数据", Toast.LENGTH_SHORT).show();
}else if (cursor.getCount()!=0) {
while (cursor.moveToNext()) {
mTvShow.append("\n"+"Name :"+cursor.getString(cursor.getColumnIndex("name"))
+"Tel :"+cursor.getString(cursor.getColumnIndex("phone")));
}
}
cursor.close();
db.close();
break;
case R.id.button2:
db = myhelper.getWritableDatabase();
values = new ContentValues();
values.put("phone", phone = mEtPhone.getText().toString());
db.update("information", values, "name =?", new String[] {mEtName.getText().toString()} );
Toast.makeText(this, "信息已修改", Toast.LENGTH_SHORT).show();
db.close();
break;
case R.id.button4:
db = myhelper.getWritableDatabase();
db.delete("information", "name= ?", new String[] {mEtName.getText().toString()});
Toast.makeText(this, "信息已删除", Toast.LENGTH_SHORT).show();
mTvShow.setText("");
db.close();
break;
}
}
}
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.homework2.MainActivity" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="20dp"
android:layout_marginTop="70dp"
android:text="姓 名:"
android:textSize="25dp" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_marginTop="21dp"
android:layout_toRightOf="@+id/textView1"
android:text="通 信 录"
android:textSize="25dp"
android:textStyle="italic" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:layout_marginTop="29dp"
android:text="电 话:"
android:textSize="25dp" />
<EditText
android:id="@+id/editText1"
android:layout_width="190dp"
android:layout_height="30dp"
android:layout_alignBaseline="@+id/textView2"
android:layout_alignBottom="@+id/textView2"
android:layout_alignParentRight="true"
android:background="#fff"
android:ems="10" />
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/button2"
android:layout_alignRight="@+id/editText1"
android:layout_toRightOf="@+id/textView3"
android:text="查 询"
android:textSize="20sp"
android:onClick="Click"
android:background="#00bfff"
android:textColor="#fff"/>
<Button
android:id="@+id/button2"
android:layout_width="250dp"
android:layout_height="wrap_content"
android:layout_below="@+id/button1"
android:layout_marginTop="21dp"
android:layout_toLeftOf="@+id/editText1"
android:text="修 改"
android:textSize="20sp"
android:onClick="Click"
android:background="#00bfff"
android:textColor="#fff"/>
<EditText
android:id="@+id/editText2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/textView2"
android:layout_alignLeft="@+id/editText1"
android:layout_alignTop="@+id/textView1"
android:background="#fff"
android:ems="10" />
<Button
android:id="@+id/button1"
android:layout_width="250dp"
android:layout_height="wrap_content"
android:layout_below="@+id/editText1"
android:layout_marginTop="16dp"
android:layout_toLeftOf="@+id/editText1"
android:text="添 加"
android:textSize="20sp"
android:onClick="Click"
android:background="#00bfff"
android:textColor="#fff"/>
<Button
android:id="@+id/button4"
android:layout_width="115dp"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/button2"
android:layout_alignBottom="@+id/button2"
android:layout_alignLeft="@+id/button3"
android:layout_alignRight="@+id/button3"
android:background="#00bfff"
android:textColor="#fff"
android:onClick="Click"
android:text="删 除"
android:textSize="20sp" />
<TextView
android:id="@+id/tv1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/button2"
android:layout_alignRight="@+id/button4"
android:layout_below="@+id/button4"
/>
</RelativeLayout>
![](https://img2018.cnblogs.com/common/1785784/201911/1785784-20191106145959650-9574030.png)
![](https://img2018.cnblogs.com/common/1785784/201911/1785784-20191106150051546-1132668943.png)
![](https://img2018.cnblogs.com/common/1785784/201911/1785784-20191106150302426-1598010325.png)
![](https://img2018.cnblogs.com/common/1785784/201911/1785784-20191106150342425-1906542514.png)
![](https://img2018.cnblogs.com/common/1785784/201911/1785784-20191106150503688-1009457818.png)